1. Field of the Invention
The present invention relates to a ball striking cue comprising butt and shaft sections that can be dismantled. More specifically, the ball striking cue according to the invention comprises a self-locking joint for removably interconnecting the butt and shaft sections end to end.
2. Brief Description of the Prior Art
Ball games such as pool, carom billiards and snooker are played with a ball striking cue. These games are played on a table comprising a baize-covered horizontal surface surrounded by a cushion mounted on a peripheral rail.
In the case of pool and snooker, the table further comprises four corner pockets as well as two side pockets. The ball striking cue is used to strike a cue ball for thereby projecting that ball toward a second ball directly or through at least one bounce on the cushion. The cue ball then strikes the second ball to move the latter ball toward one of the pockets directly or through at least one bounce on the cushion.
For many reasons that will be apparent to those of ordinary skill in the art, the above mentioned ball games require transfer of a precisely controlled level of energy from the ball striking cue to the cue ball at each play; a successful play may require either power or restraint depending on the particular circumstances.
At each play, a player must not only pocket a ball but also place the cue ball in view of pocketing another ball at the next play. A player has therefore to develop a skill to determine precisely the energy required each time it strikes the cue ball. As a precisely controlled level of energy is transferred to the cue ball through the ball striking cue at each play, the cue should be a precise instrument having specific properties.
Generally speaking, the quality of a ball striking cue is function of two properties: its "response" and its "resonance". When an equilibrium between these two properties is reached, it is said that the ball striking cue has a good "feeling".
The "response" of a ball striking cue is good when the energy from the arms and hands of the player is efficiently transferred to the cue ball. With no energy loss involved, it is easier to produce effects such as back spin, top spin and side spin of the cue ball since the player has not to compensate for the loss of energy in the ball striking cue. This prevents a player to overcompensate or undercompensate the loss of energy in the cue and thereby miss a play.
Upon striking the cue ball, the resistance to movement of that ball will produce a "feedback" along the longitudinal geometrical axis of the ball striking cue. This "feedback" is perceived by the hands of the player to help him to gauge the level of energy to be applied to the cue ball to complete a given play. Indeed, no ball striking cue is perfectly rigid whereby a cue, in particular the shaft section thereof, will bend upon striking the cue ball to thereby produce mechanical vibrations ("resonance") perceived by the player's hand to give to that player a "feeling" of each impact between the tip of the ball striking cue and the cue ball. As bending of the ball striking cue is proportional to the level of energy involved in the impact, the player will also "feel" this level of energy. It is said that a ball striking cue has a good "resonance" when:
the level of vibrations is not sufficiently high to render control of the above mentioned various effects difficult; and PA1 the vibratory wave front propagating through the ball striking cue is not perturbed. PA1 a proximate end of the other of the butt and shaft sections having an axial extension including a free end and an uniformly tapering outer surface.
Because of its particular composition, wood is well suited for the fabrication of ball striking cues. More specifically, wood provides the required characteristics of "response" and "resonance". Although ball striking cues made of other materials are available on the market, those made of wood are the most popular. Indeed, most of the players are considering that a one-piece ball striking cue made of wood presents the best equilibrium between the "response" and "resonance" properties.
However, a one-piece ball striking cue made of wood presents two major drawbacks: it is both bulky and susceptible of warping. To facilitate transport thereof, ball striking cues formed of butt and shaft sections made of wood and that can be easily dismantled and assembled have appeared on the market. Wide acceptance of these two-piece ball striking cues was rapidly noted. As bulkiness of such cues is reduced, transport and storage thereof is greatly facilitated. Moreover, the length of the pieces of wood, namely the butt and shaft sections being reduced, the tendency of such cues to warping is also reduced by 30% to 50% depending on the position of the joint between the butt and shaft sections.
Ideally, a two-piece ball striking cue should present the same properties, i.e. the same "response" and "resonance" as a one-piece cue made of the same wood. In practice, this requirement has not been met by the prior art since relatively simple mechanical joints have been used to replace the complex arrangement of wood fibers. This obviously changes the distribution of forces in the ball striking cue and accordingly the general behavior of the cue.
The prior art joints usually comprise threaded stud and hole formed on the proximate ends of the butt and shaft sections, respectively. To assemble the butt and shaft sections end to end, the threaded stud is screwed in the threaded hole. The prior art joints therefore comprise annular and flat abutment surfaces perpendicular to the longitudinal axis of the cue.
The "resonance" of a ball striking cue is mainly determined by the quality of the wood. Where the wood has a high uniform density and a substantially straight grain, the cue is rigid and stable. Upon an impact, vibrations are produced and propagate through the shaft section of the ball striking cue from the tip toward the butt section thereof. However, as the vibratory wave front reaches a prior art joint of which the density is different from that of wood, the laws of physics teach that propagation of the wave front will be perturbed by this sudden change of density of the transmission medium. Accordingly, the joint constitutes a parasitic element perturbing propagation of the wave front before it reaches the butt section and the hands of the player.
Also, the two annular abutment faces are perpendicular to the wood fibers and connected together only through the threaded stud and hole whereby they form a barrier impeding propagation of the vibratory wave front from the shaft section to the butt section.
Moreover, upon an impact between the tip of the ball striking cue and the cue ball, the feedback tends to separate the two annular flat abutment faces to an extent depending on the level of energy involved.
Depending on the material used to fabricate a prior art joint, the "response" and/or "resonance" is affected. For example, prior art joints made of stainless steel form a cue having an excellent "response" but a sharp and hard "resonance"; it is then said that the cue "gives to the player a lot of ball contact feeling". Regarding prior art plastic joints, for example made of Implex (Trademark), Delrin (Trademark) and multipolymers, they provide a "resonance" close to that of one-piece wood cues but reduce the "response".